Spaceborne desperate radiation, sight loss, and bruised bones are just some of the challenges scientists must overcome before astronauts step on Mars, NASA experts and officials said Tuesday.
The US space agency believes that a man can fall on a red planet in the next 25 years, but the technical difficulties and medical challenges that can occur are enormous.
NASA astronaut Tom Jones said, "If you have a current budget or more, it will take about 25 years to solve this task.
"We have to start with certain core technologies," he told reporters in Washington.
Mars, about 225 million kilometers, is a greater challenge than Apollo to the moon.
Astronauts can take up to nine months to arrive at Mars and the physical cost of floating too long in zero gravity will be enormous.
Scientists, for example, think that this can cause irreversible changes in the blood vessels of the retina, resulting in decreased vision.
Also, under zero gravity, the skeleton will begin to lose calcium and bone tissue.
With just one-third of the Earth's gravity, experts still do not know the effect of a one-year mission on the surface of Mars.
One way to reduce the damage to the human body is to significantly reduce the travel time to the planet.
Jones believes the nuclear propulsion system has the added benefit of producing energy in flight.
"If we start now, 25 years from now, we will be able to take advantage of technology to protect us from these long journeys.
In today's conditions, one leg of a Mars trip will take too long and the astronaut will receive the same amount of radiation that is considered safe throughout his career.
"There is still no safety solution in terms of protection of the spacecraft and astronauts exposed to solar flares during this transit time," Jones said.
Experts have identified several technologies that need to be developed quickly, including the ability to withstand harsh entry to Mars and the ability to return passengers to Earth.
NASA has a new robotic landing module called InSight for Mars that will take off from California on May 5th and land on November 26th.
The $ 993 million project aims to broaden knowledge of the Mars condition and send out explorers and clarify how Earth-like rock planets were formed billions of years ago.
Jim Garvin, chief scientist at NASA's Goddard Space Flight Center, believes that InSight completes "the things of the critical illusion" and helps clear understanding of Mars.
In 2020, other NASA missionaries will determine the residence of the Mars environment, find signs of ancient life, and send vehicles to the planet to assess the natural resources and risks of future human explorers.
In addition, private companies such as SpaceX and other countries are developing technologies that can be used for future missions to Mars.